1. Field of the Invention
The present invention relates to a method of manufacturing an opto-electric device.
2. Related Art
An opto-electric device is a device that provides for an optical effect in response to an electric signal, or that generates an electric signal in response to an optical stimulus. Examples of the first are light emitting diodes, such as organic light emitting diodes and electro chromic devices. Examples of the second are photo voltaic cells and optical sensors.
For large area OLED lighting on flexible plastic substrates, a large current is required to drive the system. The present thin film materials used for the anode (e.g. ITO) and cathode (e.g. Ba/Al) have a large resistivity and the large currents give rise to a substantial voltage drop, resulting in an inhomogeneous light emission. For producing large area flexible OLED devices on plastic substrates there is a need for additional shunting structure of the plastic substrate. Accordingly, for opto-electric devices, such as light emitting devices and electro-chromic devices, but also for photo-voltaic products there is a need for a shunting structure that on the one hand has a good electrical conductivity, while on the other hand has a high transmission for radiation.
The shunting structure should provide for a relatively high electrical conductance as compared to the transparent electrically conductive layer, but should not hinder transmission of light to or from the functional layer too much. In order to achieve a good transmission for photon radiation the shunting structure usually is formed of elongate elements, e.g. arranged in a maze-like structure that have a relatively small width (i.e. their dimension in a plane parallel to the transparent electrical conductive layer and transverse to their length). In order to achieve a sufficient electrical conductivity the elongate elements should have a relatively large height (transverse to the plane defined by the transparent electrically conductive layer). Due to the height profile of such a shunting structure it is difficult to deposit the functional layers of the device thereon. Care has to be taken to prevent shortcuts between protruding parts of the shunting layer and an electrode layer opposite the electrode layer shunted by the shunting structure. On the other hand if the shunting structure is applied after the functional layer structure, care has to be taken not to damage the functional structure by exposing it to heat or moisture.